Combined techniques for the safe correction of very large tibial rotational deformities in adults

Kevin D Tetsworth1, John David Thorsell21 Department of Orthopaedic Surgery, Royal Brisbane and Women's Hospital; Division of Surgery, School of Medicine, University of Queensland, Herston, Queensland; Orthopaedic Research Centre of Australia, Brisbane, 4029, Australia2 Department of Orthopaedic Surgery, Royal Brisbane and Women's Hospital, Queensland, Australia

Background: There are few publications specifically discussing the correction of tibial rotational deformities in adults; there are none to our knowledge that address very large deformities, exceeding 45°. We describe here a combination of reliable and predictable techniques for the safe correction of very large tibial rotational deformities.Methods: Retrospective review of a case series of eight adult patients who underwent correction of very large tibial rotational deformities following this surgical treatment protocol, with a minimum 2-year follow-up. These techniques included a formal peroneal nerve release, a subcutaneous anterior fasciotomy, a percutaneous Gigli saw corticotomy, an intramedullary nail, temporary circular external fixation, and gradual correction. The average magnitude of the preoperative rotational deformity measured 54° (45-65°). Seven of the patients had very large external rotation deformities; one had a very large posttraumatic internal rotation deformity (65°).Results: These deformities, all exceeding 45°, were successfully corrected to clinically neutral in eight consecutive cases. For all eight cases, the deformity was fully corrected within 2 weeks, and the patients returned to theater for a planned second minor procedure (locking screw insertion and external fixator removal) at an average of 9.6 (6-14) days after the index procedure. Patients were encouraged to resume full weight bearing by 6 weeks and all were walking unaided by 12 weeks. Clinical and radiographic union was achieved at an average of 15.5 (12-20) weeks. One case was over-corrected 5°; a second procedure was required to revise the deformity correction to clinically neutral. There were no other complications in this series.Conclusions: This combination of surgical techniques has, in this small series, been a consistently safe and effective treatment for this condition.

Rotational deformities are not uncommon, but frequently overlooked; [1] they have heretofore received little attention in adults. They are often missed completely and even when recognized can be difficult to quantify accurately. [1] Staheli has clearly described methods for assessing the rotational profile in children, [2],[3] yet many clinicians still find it difficult to distinguish subtle rotational abnormalities in adults. Considering the potential difficulties with clinical assessment of rotation, [1] as expected, there has been very little orthopedic literature discussing tibial rotational deformity correction in adults. The vast majority of prior publications describe the correction of rotational deformities in pediatric patients with congenital or developmental anomalies. [4],[5],[6],[7],[8],[9],[10],[11] The only literature available regarding adult rotational deformity focuses on the possibility of malunion following intramedullary nailing of fractures. [12],[13],[14]

Several methods are currently used to correct deformities of long bones, which can then be stabilized either with plates, intramedullary rods, or external fixation. [15],[16],[17],[18],[19] In the broadest sense, one could consider acute and gradual correction as two potential alternatives. Although acute correction is often the simplest method, the surrounding soft tissues generally dictate the rate, ease, and safety of correction. [18] Both nerves and vessels will only tolerate moderate stretch and will, therefore, be at genuine risk for developing significant complications such as compartment syndrome or peripheral nerve palsy. [18],[20],[21],[22] To avoid these problems, Ilizarov's methods of gradual correction using external fixation have been adopted with great success, [23],[24],[25],[26],[27] and highly accurate correction of alignment and joint orientation can be achieved while minimizing the risk of adverse events. [25],[27]

There are well-described techniques to correct malalignment in the coronal plane, in the sagittal plane, and in those oblique planes between the standard anatomic planes. [28],[29],[30],[31],[32],[33] Restoring a normal mechanical axis, with co-linearity of the hip, knee, and ankle, is one of the most basic principles of deformity correction. Joint orientation, the relationship of each of these three joints to the mechanical axis of the femur or tibia, must also be simultaneously restored to normal. [28],[29],[30],[31],[32],[33] Systematic deformity correction to achieve these goals involves meticulous preoperative planning, as has been described in detail previously. [28],[29],[30],[31],[32],[33] However, there has been far less interest in the evaluation, planning, and correction of any associated rotational deformities. Although a number of prior publications discuss rotational deformity correction in children, [4],[5],[6],[7],[8],[9],[10],[11] the magnitude of the deformities corrected has been generally of only moderate magnitude and entailed far less risk of catastrophic complications if corrected acutely.

We describe here a set of reliable and predictable techniques for either acute or gradual correction of very large tibial rotational deformities [Figure 1]. We have arbitrarily chosen to consider only those deformities exceeding 45° because in our opinion, these are at much greater risk of potential iatrogenic injuries to either nerves or vessels. [18],[20],[21],[22] We clarify when acute correction can be considered, as well as provide details of the specific methods used in this series of patients. These techniques include a formal peroneal nerve release at three discrete levels, [34] a subcutaneous anterior fasciotomy, and a percutaneous Gigli saw corticotomy. [35] We further discuss our experience managing these deformities, typically incorporating temporary external fixation together with intramedullary nails for gradual correction of very large tibial rotational deformities in adults.

The procedure begins with release of the peroneal nerve through a 4 cm oblique incision anterior and medial to the fibular neck. [34] The common peroneal nerve is first identified and released lateral to the fibular neck, and then the deep peroneal branch is decompressed [Figure 2]. This requires transverse division of the adjacent fascia and identification of the septum between the anterior and lateral compartments, directly medial and anterior to the fibular neck. [34] This dense band of fascia is isolated, and sectioning this septum toward the fibular neck under direct vision completes the second release. A fibro-osseous tunnel still encases the deep branch as it passes beneath the origin of the peroneal muscles, and a third release is required. This remaining fibrous band is released directly anterior to the fibula, to complete full decompression of the nerve at three discrete levels. [34] Through this same incision, the fascia of the anterior compartment is released percutaneously. A fibular osteotomy was performed in most cases, to limit torque on the tibio-fibular articulations, both proximal and distal.

A percutaneous Gigli saw corticotomy [35] was most often performed in the proximal tibial metaphysis, as this type of osteotomy is ideally suited to rotational deformity correction. The specific details for performing the Gigli saw corticotomy have been described previously. [35] Two small transverse incisions, one directly anterior and one directly medial, are used to create sub-periosteal tunnels along the lateral and posterior surfaces of the tibia, several centimeters distal to the tibial tubercle. A heavy suture is passed through this sub-periosteal tunnel, and this in turn is used to pass the Gigli saw. [35] The corticotomy is performed at this point leaving the medial cortex intact, only completing the corticotomy after the intramedullary nail is already in position [Figure 3]. We used a Trigen (Smith-Nephew, Memphis, Tennessee, USA) intramedullary nail, locked proximally through the attached insertion jig; the distal locking holes were left empty to allow the distal fragment to initially rotate freely. Whenever external fixation is used in combination with internal fixation or an intra-medullary nail, it is important to avoid contamination of the implant. Care needs to be taken during this procedure to limit the risk of contact between the half pins and the nail, with fluoroscopic views as necessary. The Taylor spatial frame (TSF) (Smith-Nephew, Memphis, Tennessee, USA) was used when indicated for gradual correction over an intramedullary nail, and the corticotomy completed after the TSF was applied [Figure 4] and [Figure 5]. The Ilizarov method of gradual correction using the TSF provides a versatile technique for correction of all aspects of a tibial deformity. [23],[24],[25],[26],[27],[28] This device is very precise, and facilitates highly accurate correction of skeletal deformities. [25],[27]

Posttraumatic deformities localized to the distal tibia were considered at less risk and were corrected acutely. In six cases, in this series, the rotational deformity was corrected gradually and in two cases acutely. One acute correction was performed over an intramedullary rod through a proximal Gigli saw corticotomy, a correction from 65° internal to neutral. The other acute correction involved a revision ORIF of a distal tibial fracture initially fixed in 45° external rotation. In the six remaining cases, gradual correction using the TSF was performed at a rate of 10-15°/day. No perioperative complications were encountered. All patients received prophylactic antibiotics at induction of anesthesia and were administered chemical venous thromboembolism (VTE) prophylaxis in accordance with local guidelines. After the deformity was fully corrected clinically, the patient returned as planned for a separate small procedure for insertion of the distal locking screws and removal of the fixator [Figure 6], within 2 weeks of the index procedure. Patients were encouraged to partial weight bear thereafter, under the supervision of physiotherapists.

Figure 6: Immediate postoperative views following insertion of distal locking screws and removal of the temporary external fixator, with antero-posterior and lateral views

We conducted a retrospective review of a series of eight patients who underwent correction of very large tibial rotational deformities by a single surgeon at a major metropolitan tertiary hospital. Our institution's Human Research Ethics Committee granted prior approval to conduct this study, and all patients gave written consent to participate prior to the study, in accordance with the Ethical Standards of our Institutional Committee on Human Experimentation and with the Helsinki Declaration of 1975, as revised in 2000. Selection criteria included age >16 years; symptomatic tibial rotational deformities that had failed to respond to nonoperative measures including activity modification and oral anti-inflammatories and follow-up >2 years postoperative. A standard protocol was developed for the systematic correction of tibial rotational deformities exceeding 45°, affecting eight limbs in seven patients (one bilateral case). Those patients included four women and three men and involved five right and three left tibiae. The etiology was posttraumatic in three cases and developmental in five cases, and the patient's average age was 31.2 (17-47) years. The average magnitude of the preoperative rotational deformity measured 54° (45-65°). Seven of the patients had very large external rotation deformities and only one had a very large posttraumatic internal rotation deformity (65°).

Rotational profiles of both lower limbs were assessed carefully using clinical examination only. Rotation of the lower limbs was assessed completely and documented both preoperatively and postoperatively, following a thorough, comprehensive physical examination. The magnitude of the rotational deformity was measured using a goniometer, with the patient prone, supine, and seated. A smart phone app was used to measure clinical rotation parameters for several of these patients later in the case series. [36] The rotational profile was recorded, including the foot-progression angle during gait, the thigh-foot angle when prone, femoral anteversion, femoral torsion, and tibial torsion.

Specific maneuvers were used during the physical examination that have been found to be the most useful in clinical practice. Because the knee acts largely as a hinge confined to a single plane, it is the most constrained joint of the lower extremity. Recognizing this inherent constraint, the axis of the knee can be considered the most important functional consideration with respect to rotation of the lower limb. The flexion axis of the knee (FAK) was, therefore, used as a convenient and easily defined plane of reference and served as the starting point for assessing both femoral and tibial rotation. Femoral anteversion was measured with the patient prone and the knee flexed 90°, and the prominence of the greater trochanter palpated through a range of internal and external rotation. When the trochanter was most prominent, the angle of the tibia relative to vertical was used as an indirect measure of femoral anteversion. Femoral and tibial torsion were assessed with the patient supine and both the hip and knee flexed 90°, with the femur oriented vertically. Femoral torsion was determined by measuring the orientation of the FAK relative to the transverse axis of the pelvis. In this series of patients, femoral torsion was excluded in each case but one, which had an additional concomitant femoral malunion. Tibial torsion was measured with regard to the orientation of the axis of the ipsilateral foot relative to the FAK. When the opposite limb was considered normal, the magnitude of deformity was recorded as the difference in the measured rotational profile between the two limbs. For bilateral cases, normal rotation was considered when the first web space of the ipsilateral foot was oriented orthogonal to the FAK.

Results

Very large tibial rotational deformities, all exceeding 45°, were successfully corrected to clinically neutral in eight consecutive cases. For all eight cases, the deformity was fully corrected within 1 week, and the patients returned to theater for a planned second minor procedure (locking screw insertion and external fixator removal) at an average of 9.6 days after the index procedure (6-14). There was over-correction from 60° external to 5° internal in one case that was corrected to neutral rotational alignment during an additional unplanned procedure several days later. At 1 year, the rotational profile was re-assessed by two surgeons, and in all eight cases the malrotation was corrected to <5° residual deformity and clinically symmetric. There were no cases of compartment syndrome and there were no neurologic injuries associated. Patients were encouraged to resume full weight bearing by 6 weeks and all were walking unaided by 12 weeks. Clinical and radiographic union [Figure 7] and [Figure 8] was achieved at an average of 15.5 weeks (12-20). There were no delayed or nonunions and all corrective osteotomies healed spontaneously without the need for bone graft or other factors to enhance union. One additional procedure was required to correct the minor over correction as noted above. This involved removal of the distal locking screws, manipulation of the distal tibia, and re-insertion of the locking screws with the rotation corrected to neutral. There were no infections, deep venous thrombosis/VTE, deaths, or other complications.

Figure 7: Radiographic views at 14 weeks, with antero-posterior and lateral views; the corticotomy has already progressed toward early union

Rotational deformities have previously received little attention in adults, and they are often inconspicuous. [1] However, they are not uncommon, but are instead frequently missed; even when recognized, they can be difficult to quantify accurately. [1] Although Staheli has identified very specific methods for assessing the rotational profile in children, [2],[3] many clinicians still find it difficult to distinguish subtle rotational abnormalities in adults, particularly during gait. Paradoxically, some gait disturbances appear transient and manifest only during the swing phase, then seem to spontaneously correct during the stance phase. Because the hip is round, patients may simply orient their involved foot directly forward with heel strike despite the presence of a rotational deformity, regardless of the orientation of the more proximal joints. The corresponding malorientation of the hip and knee are often not apparent, and patients can easily mask even moderate rotational deformities. Unfortunately, these same patients may later present with significant complaints of hip and knee pain associated with chronic malorientation of these joints to their intended path. [37],[38],[39],[40],[41],[42],[43],[44]

The systematic analysis of deformities and their formal preoperative planning has played a vital role in the development of surgery specifically for deformity correction as a sophisticated orthopedic sub-specialty. [28],[29],[30],[31],[32],[33] This has been a topic of considerable activity for the past 25 years, driven in part by interest in the methods of Ilizarov. The introduction of his methods and the further development of other dynamic external fixators has allowed for the gradual correction of deformities that previously were much more difficult to treat. [23],[24],[25],[26],[27],[28] Unfortunately, prolonged use of external fixation, while profoundly effective, can be cumbersome and particularly difficult for adult patients. Furthermore, its use can be associated with a significant risk of pin tract infections and other complications. [22]

Fortunately, technological advances with respect to intramedullary nails and other internal fixation devices have complimented this interest in deformity correction, and innovative techniques have been introduced that combine gradual correction using external fixation with less invasive forms of definitive stabilization. These disparate elements have all conspired now that allow adult patients to consider correction of deformities they have tolerated, with some limitations and associated disability for many years previously. Of particular interest here, many of these neglected deformities have a significant rotational component.

Skeletal deformity has many potential elements including angulation, translation, length, and rotation, and these may be present individually or in combination. Axial alignment is the one aspect that is most often discussed and must be considered with regard to both the coronal and sagittal planes. [23],[24],[25],[26],[27],[28] Normal lower extremity alignment is a recognized prerequisite for a mechanically efficient bipedal gait. [42] Whether the etiology is congenital, developmental, or posttraumatic, deformity will inevitably distort the normal relationship of the components of the lower extremity to each other. Even mild disturbances of lower limb alignment, either angular or rotational, have the potential to result in abnormalities of gait and influence function. This can also have significant deleterious biomechanical consequences and may alter the transmission of force across joints, leading to aberrant cartilage loading. If the deformity is of sufficient magnitude, over a period of years, these abnormalities in load can result in premature arthritic degeneration, [37],[38],[39],[40],[41],[42],[43],[44],[45] which thereafter can further affect gait and function.

Nerve injury is one of the most serious complications associated with limb lengthening and deformity correction. [20],[21],[22] In a retrospective study [21] of 814 limb-lengthening procedures, 9.3% of lengthened limbs had a nerve lesion. The vast preponderance (84%) of these lesions occurred during gradual distraction, with far less (16%) noted immediately after surgery. These acute nerve injuries were present even though nerve decompression had been performed in 70% of these cases. [21] Acute methods of deformity correction are more often complicated by nerve palsy and many of these cases develop chronic neurogenic pain; [20],[21],[22] nerve injury is less common with gradual lengthening. [21],[22] In our opinion, peroneal nerve release [34] should be considered most often when proximal tibial deformities are corrected acutely, taking into consideration not only rotation, but also coronal and sagittal plane deformities. We believe it is most prudent to consider prophylactic nerve release whenever the sum of the magnitude of the deformities in all three planes (external rotation, valgus, knee flexion contracture, and procurvation), in any combination, exceeds 30°.

Whether to perform the rotational correction acutely or gradually is a decision that must be carefully considered, and [Table 1] provides general guidelines that can assist in making that decision. Correction of femoral rotational deformity is much less risky, and the vast preponderance of both internal and external rotation femoral deformities can be corrected acutely, regardless of their magnitude. [15],[16],[17] Correcting a tibial rotational deformity is at significantly greater risk of either nerve injury or compartment syndrome and this is true for both internal and external rotation. [21],[22] For tibial deformities, consideration must be given to the level of the corrective osteotomy, the magnitude of the deformity, and the direction involved, as well as the chronicity of the condition. Proximally, the peroneal nerve is at greatest risk; distally, both the posterior tibial artery and nerve are at risk and can be injured with acute corrections. Recently, generated posttraumatic rotational deformities tolerate acute correction, [15],[16],[17] more readily than congenital or developmental deformities, as is true of other types of deformity.

Table 1: General guidelines when considering either acute or gradual correction of rotational deformities in adults

The strength of this study lies in the systematic and consistent application of the same series of surgical techniques to very large tibial rotational deformities of diverse etiology. Limitations of this study principally reflect its design as a case series, with only a small number of subjects. There was no control group, and patients were not formally assessed using validated outcome measures. Future randomized studies could compare operative to nonoperative treatment using both objective and subjective measures of function and patient satisfaction. Despite these limitations, this is one of the very few studies to address correction of rotational deformities in adults; it is to our knowledge the only study to specifically address very large tibial rotational deformities exceeding 45°, regardless of patient age or etiology.

Conclusion

There are few, if any, prior publications to guide our treatment of very large rotational deformities in adults. There is a significant risk of compartment syndrome and neurologic injuries if tibial rotational deformities are corrected acutely, [21],[22] particularly when the deformity exceeds 45°. We describe here a treatment approach using various surgical techniques that in our experience allows this to be performed with confidence. The combination of peroneal nerve release, [34] percutaneous fasciotomy, Gigli saw corticotomy, [35] intramedullary nail, temporary circular external fixation, and gradual correction has, in this small series, been a consistently safe and effective treatment for this condition.

Financial support and sponsorship

Nil.

Conflicts of interest

The senior author (KDT) is a consultant with Smith and Nephew, plc and Stryker Corp, and devices used and mentioned in this study are coincidentally manufactured by Smith and Nephew. The senior author (KDT) is on the Speakers Bureau for Smith and Nephew, plc and Stryker Corp, and devices used and mentioned in this study are coincidentally manufactured by Smith and Nephew. There is no direct conflict or connection between these relationships and the subject of this manuscript.